I installed WSL (Ubuntu 18.04) on Windows 10 to use instead of using parallel 2 OS. However, when I was using shebang, I couldn't run the script named test_file.py successfully. First, I created a folder named test_project. In this folder, I created:
An src folder that contains a simple Python script is shown as follows
#!/usr/bin/env python3
print("Hello world")
A Python environment folder named environment through python3 -m venv environment/ (I'm using Python 3.6)
The problem is when I stepped into the environment and typed some commands like in the attached picture Run python file, the program ran "command not found" although I already used shebang at the beginning of the code.
Apart from that, I also changed #!/usr/bin/env to #!/usr/bin/python3 and escape the environment, it didn't work as well. Only when I type Python3 test_file.py it worked.
Has anyone faced this problem before? Can anyone explain to me why this happens? I'm wondering whether it is different between using WSL compared to Ubuntu in this case, or I was missing some steps during coding. I know that this problem is debated common previously, however I couldn't find any source that can tackle my problem. I really appreciate all your help.
I had the same issue and resolved it by the changing the line endings from CRLF which is native to Windows to LF which is what the shell is expecting.
You can do this with the dos2unix command:
dos2unix -b test_file.py
You'll probably need to install dos2unix on some newer distributions.
There are other methods that can be used as well.
Related
I have a program in a directory ~/trevor. Using Ubuntu, if I cd to this directory then I can execute this program with
$./program
However, I want to be able to execute this program from within a Python script, but when I try using
import subprocess.run
subprocess.run("./program")
I get the following error:
OSError: [WinError 193] %1 is not a valid Win32 application
How can I solve this?
I am running the python script through Pycharm's terminal. It has occurred to me that I could run the python script through Ubuntu's terminal, but then I have a problem with Ubuntu finding the correct packages. I am running Windows with a Ubuntu shell - I tried solving the Ubuntu package problem by changing Ubuntu's PYTHONPATH to the same path as Pycharm's project interpreter, but this didn't work either. I thought it would be easier to solve the problem above than to the package problem.
Thanks for the help.
As previously discussed in comments, and then included in an edit to the question:
The mistake was trying execute a Ubuntu program through a Windows command line. The solution here was to execute the Python script (with subprocess.run() or subprocess.call()) through the Ubuntu command line.
Insofar as executing Python on Ubuntu can't find Python packages/modules, this is because those packages/modules were installed through the Windows command line, so native/compiled dependencies they included were built for Windows rather than Ubuntu. Even if Ubuntu's PYTHONPATH is pointed to the location of the packages, there are some modules that won't work because they have platform-native components. The solution is to download the package again but through Ubunutu (such that they are suitable for a Linux distribution).
os.exec* typically works for both windows and linux as far as I'm aware, however it does require an a letter or two that replace the "*" in certain situations. You'll have to look at this to see which one you would need https://docs.python.org/2/library/os.html
ex. os.execl or os.execle
subprocess.call is an older version that will avoid a lot of the problems with shell specific conventions. If the issue is Ubuntu-nativity as the comment above suggests, this could fix it.
I just installed my ubuntu on my PC then i installed python 3 & Vscode on my PC. but my VS Code didn't recognize the python3. maybe my vs code looking for my python. how to solve this?
In my VS Code when I compiled the class then the output:
python -u "/home/kisiniki/Documents/python/tempCodeRunnerFile.py"
/bin/sh: 1: python: not found
In my terminal already installed python 3.6.8.
First, try to see if you are able to run the same command in terminal.
python -u "/home/kisiniki/Documents/python/tempCodeRunnerFile.py"
If you are getting the same error, "python: not found", then likely python installation was not completely successful, you can either uninstall and reinstall or you can try to update PATH to contain the folder containing the python executable. See https://askubuntu.com/questions/637848/how-to-reset-python-path-to-usr-bin-python for more detail.
If you can run the command in terminal, then that means VS Code cannot find your installed python. See if you need to edit some settings in VS Code for it to know what python executable to run. See
https://code.visualstudio.com/docs/python/environments for more detail.
It's probably because you used the command python without having an activated virtual environment or not using python3 or python3.6. Try it with python3.6 and see if that fixes it. If it doesn't then Python isn't on your PATH.
I am using Python 3.5.2 version on Windows 7 and tried using python3 app.py. I am getting this error message:
'python3' is not recognized as an internal or external command,
operable program or batch file.
Is there any specific cause about why the python3 command is not working?
I also verified that the PATH is added to environment variables.
There is no python3.exe file, that is why it fails.
Try:
py
instead.
py is just a launcher for python.exe. If you have more than one python versions installed on your machine (2.x, 3.x) you can specify what version of python to launch by
py -2 or
py -3
You can also try this:
Go to the path where Python is installed in your system. For me it was something like C:\Users\\Local Settings\Application Data\Programs\Python\Python37
In this folder, you'll find a python executable. Just create a duplicate and rename it to python3. Works every time.
Python3.exe is not defined in windows
Specify the path for required version of python when you need to used it by creating virtual environment for your project
Python 3
virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment
Python2
virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment
then activate the environment using
.\environment\Scripts\activate.ps1
Yes, I think for Windows users you need to change all the python3 calls to python to solve your original error. This change will run the Python version set in your current environment. If you need to keep this call as it is (aka python3) because you are working in cross-platform or for any other reason, then a work around is to create a soft link. To create it, go to the folder that contains the Python executable and create the link. For example, this worked in my case in Windows 10 using mklink:
cd C:\Python3
mklink python3.exe python.exe
Use a (soft) symbolic link in Linux:
cd /usr/bin/python3
ln -s python.exe python3.exe
In my case I have a git hook on commit, specified by admin. So it was not very convenient for me to change the script (with python3 calls).
And the simplest workaround was just to copy python.exe to python3.exe.
Now I could launch both python and python3.
If python2 is not installed on your computer, you can try with just python instead of python3
For Python 27
virtualenv -p C:\Python27\python.exe django_concurrent_env
For Pyton36
virtualenv -p C:\Python36\python.exe django_concurrent_env
Enter the command to start up the server in that directory:
py -3.7 -m http.server
I had a related issue after installing windows 11, where python3 in cmd would open the windows store. I was able to sort it out between this post and this other one. In short, I reinstalled python and made sure to add it to PATH. Then, in settings, Apps > Apps & Features > App Execution aliases. Here, all I had to do was make sure that every single python .exe (including idle and pip) were turned off EXCEPT FOR the python3.exe alias. Now it works like a charm.
FWIW:
The root of this issue is not with you or with python. Apparently, Microsoft wanted to make installing python easier for young kiddos getting interested in coding, so they automatically add an executable to PATH. For those of us that already have this executable, it can cause these issues.
Found out instead press the play button the top right and it should work in visual studios:
Do not disable according to first answer
Saying python3 in the command will not work by default.
After figuring out the problem with the modules (Solution): https://youtu.be/paRXeLurjE4
Summary:
To import python modules in case of problem to import modules:
Hover over python in search:
Click open in folder
Hover over and right click
click properties
copy everything in path before \python.exe
close those windows
For cmd (administrator):
cd --path that was copied--
then python -m pip install --upgrade pip
cd Scripts
pip install "Name of Package" such as pip install --module (package) --
Im on win10 and have 3.7, 3.8 and 3.10 installed.
For me "python" launches version 3.10 and does not accept commands (like -3.7), "py" launches newest version but does accept commands, and "python3" does nothing.
Uninstalled 3.10 and "python" now does nothing, and "py" launches 3.8.
I am unable to add a comment, but the mlink option presented in this answer above https://stackoverflow.com/a/55229666/8441472 by #Stanislav preserves cross-platform shebangs at the top of scripts (#!/usr/bin/env python3) and launches the right python.
(Even if you install python from python.org, Windows will direct you to the app marketplace nowadays if you type python3 on the command line. If you type python on the same cli it will launch the python.org version repl. It leads to scripts that generate no output, but more likely silently failed completely. I don't know ho common this is but have experienced it on a couple of different devices)
If you have this at the top of your script to ensure you launch python3 and don't feel like editing everything you own, it is not a bad approach at all... lol.
I have installed Anaconda 2 & 3 in my system. Anaconda 2 contains python 2.7 & Anaconda 3 contains python 3.6.
I need to run my python code using command prompt & I need to use python 3.6
While I'm running python --version, I'm getting python 2.7.14. How do I change it to python 3.6?
As you can see, I have both Python2 and Python3 installed.
I hope you know that the path of the python executable has to be added to the PATH environment variable in Windows. As you can see, the path of Python2 is placed above the path of Python3 in my system.
How does the cmd run commands?
It searches for an executable with the same name in the directory the cmd has been opened in, then goes and searches for the command in the locations provided in the Windows PATH variable, from TOP to BOTTOM.
Which means, it gets the path to Python2 before it can get to the path of Python3. Therefore, every time you type python in your cmd, it runs Python2.
Both Python2 and Python3 executables have the same name in Windows so it never runs python3.
What seems like an obvious solution?
You might think, changing the name of python.exe to python3.exe for the Python3 executable will solve your problem. You are partially right, it will work. But you have to use python3 file.py or python3 --version, which I think, is understandable. But, pip will no longer work if you change the name of the original python executable. You will no longer be able to install external packages and modules.
How can this problem be solved?
You can create an alias for the Python3 executable called python3.bat.
.exe and .bat files can be called from the cmd directly without using their extension. We always write python filename.py instead of python.exe filename.py although both are correct. The same can be done with .bat files.
Go back to the first image and notice the python3.bat file below python.exe. That is my way of calling python3 without renaming my original python executable.
python3.bat
Create a new file using notepad or something and paste this %~dp0python %*
I don't fully understand how this works except that dp0 basically runs python from inside the same directory and %* passes all the arguments to the python executable. Place this file inside your Python3 installation directory and your problem will hopefully be solved.
python3 basically runs your python3.bat file, which in turn runs the python.exe from its folder and passes the arguments to it.
I hope this solves your problem.
You should have python3 also in your path. You could use python3 to run your script:
python3 <your_script>
But to answer your question, you could use alias and update it as python.
$ python --version
Python 2.7.6
$ alias python=python3
$ python --version
Python 3.6.4
If you want to run Python 3.6, then execute python3.6.
Otherwise, check with which python where the symbolic link to the actual python executable is. On my system, it's
/usr/bin/python
and when I ls -la /usr/bin/python, it gives
lrwxrwxrwx 42 user user 42 Aug 24 03:45 /usr/bin/python -> python2.7
If you are really sure that you want to do it, you can now just move the old symlink somewhere:
sudo mv /usr/bin/python /usr/bin/old_python
and create a new symlink:
sudo ln -s /usr/bin/python3.6 /usr/bin/python
Now you should get something like:
$ python --version
Python 3.6.5
I don't guarantee that it doesn't break everything in the world, especially if you have some distro that has a package manager that relies on a specific python version under python.
This seemed to work nicely on Linux Mint 18.
I made a small trick to solve this problem. For me
C:\Python27
and
C:\Python27\Scripts
were at the top of the PATH Environment variable list. I simply selected them and clicked on Moved Down to shift them to the end of the list.
Just make sure that your path of Python3 and its Script folder is above Python2 path.
And it solved the problem for me. Hope it would help you too.
Reason :
How does the cmd run commands?
It searches for an executable with the same name in the directory the cmd has been opened in, then goes and searches for the command in the locations provided in the Windows PATH variable, from TOP to BOTTOM. Which means, it gets the path to Python2 before it can get to the path of Python3. Therefore, every time you type python in your cmd, it runs Python2.
Both Python2 and Python3 executables have the same name in Windows so it never runs python3.
reason is taken from the accepted answer to this question.
In order to run your script with python 3 you can use
python3 <path to file>
P.S.: this should be a comment, but I do not have the required reputation. :)
If Anaconda 3's is the only python3 interpreter in the system you can run python3 instead of python in your command line and it should work.
You can alter PATH parameter inverting the positions of both interpreters.
I have two versions of the python which the first path is python 2(I am still working with python 2), but there are some scripts which should use python 3. This is what I have done:
I have create a bat file.
ex:
open Notepad++ and write :
#echo off
set PYTHONPATH=
"%~dpn0.py" %*
save it as 'yourscriptname.cmd'.
before my script(which should use python3) I just run this file in command line and then run my script. it is working.
I am trying to install Sublime Text 2 on my linux machine and I cannot figure out how to run the python script to install it. I am fairly new to linux and never programmed in python before. I am trying to run the python script PackageSetup.py using ./PackageSetup.py but i get the error:
bash: ./PackageSetup.py: python: bad interpreter: No such file or directory
not sure what I have to do. I have python on my machine. I can tell cause running 'python' puts me in the console.
For all I know this kind of issue can occur if you have a misspelling or mistake in the shebang. I see two ways to solve this issue: you can try to invoke PackageSetup.py via python, like python PackageSetup.py or you can open PackageSetup.py and try to find an issue in the shebang, maybe it needs to be a full path to python interpreter like /usr/bin/python not just python.
BTW, why don't you try to install it via some kind of package manager - there is a repo for debian-based distros, and I'm pretty sure that there have to be repositories for other distributives.